Adoption will be driven by customer need
I agree with almost everything you have stated here Martin. There is a definite case of SDS from traditional NAS/SAN through to scale out object storage (I think there may be a case for flash/hybrid arrays, where performance guarantees require dedicated platforms), but the speed of adoption will depend on a number of parameters.
1) End user/Integrator skill set
2) Knowledge of the market, options
3) Uses cases/ references
I believe the complete abstraction, ie software on ANY platform, is a little way off yet. It'll require more general confidence in the software technology first. I see no issue with compatibility lists or validated commodity hardware delivered as part of the solution, as things stand. Look at the general move towards prevalidated technical stacks such as Vblock, flexpod, vspex etc, there is huge customer demand for those type of solutions, as it removes much of the complexity and operational cost when rolling out services. I thinks we need to get to this stage first in the storage market (for all the same reasons), before we start talking about storage software on ANY platform.